1. Field of Invention
This invention relates to fastening devices, and particularly to adjustable fasteners for positioning and securing printed wiring boards to a mother board or back plane of a personal computer.
2. Description of the Related Art
Printed wiring boards are devices containing electronic circuitry and components with a specific function or functions used in computers. Add-on printed wiring boards are frequently called cards. A mother board is a master printed wiring board into which various add-on printed wiring boards are connected. Typically mother boards are provided with a series of card edge connectors into which add-on printed wiring boards are inserted. These card edge connectors are electrically coupled by means of a bus structure which defines which signals are carried to each connector pin. Mother boards also typically contain the system computer processor and other functionalities.
Add-on printed wiring boards add both functional capacity and capability to a mother board and are both physically and electronically attached to the mother board by a card edge connector. Examples include disk drive controllers, video controllers, communication functionalities, networks, memory, system interface controllers, and the like. A back plane is a master printed wiring board which add-on printed wiring boards are connected to. Typically, back planes do not have any capability of their own other than to interconnect the add-on printed wiring boards by means of a bus structure. A card cage is a mechanical enclosure of sheet metal and plastic used to house a plurality of printed wiring boards. A printed wiring board hold down device or fastener may be used to hold the printed wiring boards in place in a card cage, so as to prevent damage and movement from vibrations and shocks.
Heretofore, numerous fastening devices have been proposed and implemented to fasten and secure objects to various articles. However, there exists a need for an adjustable, reliable, and easy to use fastening means for positioning and securing printed wiring boards to mother boards or back planes used in personal computers. All prior devices have been cumbersome to use, difficult or impossible to adjust, and expensive to manufacture and replace. The present invention provides a printed wiring board fastener which is adjustable, easy to install resistant to separation at the card edge connector due to forces such as shock, vibration, expansion/contraction creep due to cycling temperatures, which is adaptable to a wide variety of printed wiring board configurations, and which is inexpensive to manufacture and replace.
Accordingly, it is the primary object of this invention to provide a printed wiring board fastener for personal computers which is adjustable, easy to install or replace in a computer, resistant to forces such as shock, vibration and expansion/contraction due to cycling temperatures, which may be installed in new computers or retro-fitted onto existing computers, and which is inexpensive to install, use, and manufacture.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.